有关对于在ArcGIS中将选中的纪录的feature调用出来

在ArcGIS中经常会需要将选中的纪录调用出来,需要使用如下一下一些接口,ISelection,IEnumFeature,IEnumFeatureSetup
以下是从官方帮助文档中提供的三种提取选择feature的代码,现贴出来以供参考

IMap FeatureSelection Example

Below are three different methods for looping through a map's selection. The first script uses IMap::FeatureSelection. The problem with this approach is that there is no guarantee all of the fields for a particular feature class are returned in the query. By default only the Shapefield is asked for as this property is primarily used to draw the map's selected features only, not access their attributes. However, this approach may be used when editing; in this case, all the fields are requested.


The second sample is the same as the first except it additionally uses IEnumFeatureSetup to explicitly tell the map to retrieve all fields.

The last sample is the best approach. It is rarely the case that one would want to loop through the entire selection in such a manner as the first two samples. The exception is of course when drawing the selected features or determining the total selection count. Instead, it is much more practical to loop through the selections belonging only to the layers of interest. For example, in a case where only selected polygons are of interest, it is much more efficient to only check the geometry type of each feature class rather than each feature returned by IMap::FeatureSelection.

Public Sub LoopThruSelection()
Dim pDoc As IMxDocument
Dim pMap As IMap
Dim pEnumFeat As IEnumFeature
Dim pFeat As IFeature

Set pDoc = ThisDocument
Set pMap = pDoc.FocusMap
Set pEnumFeat = pMap.FeatureSelection
Set pFeat = pEnumFeat.Next
Do While (Not pFeat Is Nothing)
Debug.Print pFeat.Value(pFeat.Fields.FindField("Name"))
Set pFeat = pEnumFeat.Next
Loop
End Sub


Public Sub LoopThruSelection2()
Dim pMxDoc As IMxDocument
Dim pMap As IMap
Dim pEnumFeature As IEnumFeature
Dim pEnumFeatureSetup As IEnumFeatureSetup
Dim pFeature As IFeature

Set pMxDoc = ThisDocument
Set pMap = pMxDoc.FocusMap
Set pEnumFeature = pMap.FeatureSelection
Set pEnumFeatureSetup = pEnumFeature 'QI
pEnumFeatureSetup.AllFields = True
Set pFeature = pEnumFeature.Next
Do While (Not pFeature Is Nothing)
Debug.Print pFeature.Value(pFeature.Fields.FindField("Name"))
Set pFeature = pEnumFeature.Next
Loop
End Sub


Public Sub QuerySelectedFeatures()
Dim pMxDoc As IMxDocument
Dim pEnumLayer As IEnumLayer
Dim pFeature As IFeature
Dim pFeatureCursor As IFeatureCursor
Dim pFeatureLayer As IFeatureLayer
Dim pFeatureSelection As IFeatureSelection
Dim pMap As IMap
Dim pSelectionSet As ISelectionSet
Dim pUID As IUID
'the UID specifies the interface identifier (GUID)
'that represents the type of layer you want returned.
'in this case we want an EnumLayer containing all the FeatureLayer objects
Set pUID = New UID
pUID = "{E156D7E5-22AF-11D3-9F99-00C04F6BC78E}" ' Identifies FeatureLayer objects
Set pMxDoc = Application.Document
Set pMap = pMxDoc.FocusMap

'Loop through all feature layers in the map
Set pEnumLayer = pMap.Layers(pUID, True)
pEnumLayer.Reset
Set pFeatureLayer = pEnumLayer.Next
Do While Not pFeatureLayer Is Nothing
'Loop through the selected features per layer
Set pFeatureSelection = pFeatureLayer 'QI
Set pSelectionSet = pFeatureSelection.SelectionSet
'Can use Nothing keyword if you don't want to draw them,
'otherwise, the spatial reference might not match the Map's
pSelectionSet.Search Nothing, False, pFeatureCursor
Set pFeature = pFeatureCursor.NextFeature
Do While Not pFeature Is Nothing
'Do something with the feature
Debug.Print pFeature.Value(pFeature.Fields.FindField("Name"))
Set pFeature = pFeatureCursor.NextFeature
Loop
Set pFeatureLayer = pEnumLayer.Next
Loop

End Sub


posted @ 2007-07-18 15:35  枫崖  阅读(811)  评论(0编辑  收藏  举报